This invention relates to a method of multicasting for a mobile host which is used in a network including a plurality of sub-networks connected to one another.
A network includes a plurality of sub-networks which are connected to one another and serves multicast service that a multicast packet is delivered from an originator to a set of destinations. A scope of the multicast transmission is limited by the originator on the basis of a physical network topology to form a multicast group.
The sub-networks have nodes called agents to accept a mobile host in the network and to assist the mobile host. The mobile host is related to one of the agents, this relationship determines the mobile host's home agent. The mobile host has a specific identifier called a home address which is used by the home agent to manage the mobile host.
In a conventional multicasting method, the mobile host is permitted to participate in the multicast group when the home agent is located in the scope.
However, this method has a defect that the mobile host located in the scope is not permitted to participate in the multicast group when the home agent is located outside scope. Moreover, the method has another defect that the originator can not exclude the mobile host located outside the scope from the multicast group when the home agent is located in the scope.
In another conventional multicasting method, the mobile host is permitted to participate in the multicast group when it is located in the scope.
However, this method has a defect that the mobile host located outside the scope is not permitted to participate in the multicast group though the home agent is located in the scope. Moreover, the method has another defect that the originator can not exclude the mobile host located in the scope from the multicast group even though the home agent is located outside the scope.